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		<title>three.js webgl - buffer geometry custom attributes - particles</title>
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		<div id="info"><a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> webgl - buffergeometry custom attributes - particles</div>

		<script type="x-shader/x-vertex" id="vertexshader">

			attribute float size;

			varying vec3 vColor;

			void main() {

				vColor = color;

				vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );

				gl_PointSize = size * ( 300.0 / -mvPosition.z );

				gl_Position = projectionMatrix * mvPosition;

			}

		</script>

		<script type="x-shader/x-fragment" id="fragmentshader">

			uniform sampler2D pointTexture;

			varying vec3 vColor;

			void main() {

				gl_FragColor = vec4( vColor, 1.0 );

				gl_FragColor = gl_FragColor * texture2D( pointTexture, gl_PointCoord );

			}

		</script>

		<script type="module">

			import * as THREE from '../build/three.module.js';

			import Stats from './jsm/libs/stats.module.js';

			let renderer, scene, camera, stats;

			let particleSystem, uniforms, geometry;

			const particles = 100000;

			init();
			animate();

			function init() {

				camera = new THREE.PerspectiveCamera( 40, window.innerWidth / window.innerHeight, 1, 10000 );
				camera.position.z = 300;

				scene = new THREE.Scene();

				uniforms = {

					pointTexture: { value: new THREE.TextureLoader().load( "textures/sprites/spark1.png" ) }

				};

				const shaderMaterial = new THREE.ShaderMaterial( {

					uniforms: uniforms,
					vertexShader: document.getElementById( 'vertexshader' ).textContent,
					fragmentShader: document.getElementById( 'fragmentshader' ).textContent,

					blending: THREE.AdditiveBlending,
					depthTest: false,
					transparent: true,
					vertexColors: true

				} );


				const radius = 200;

				geometry = new THREE.BufferGeometry();

				const positions = [];
				const colors = [];
				const sizes = [];

				const color = new THREE.Color();

				for ( let i = 0; i < particles; i ++ ) {

					positions.push( ( Math.random() * 2 - 1 ) * radius );
					positions.push( ( Math.random() * 2 - 1 ) * radius );
					positions.push( ( Math.random() * 2 - 1 ) * radius );

					color.setHSL( i / particles, 1.0, 0.5 );

					colors.push( color.r, color.g, color.b );

					sizes.push( 20 );

				}

				geometry.setAttribute( 'position', new THREE.Float32BufferAttribute( positions, 3 ) );
				geometry.setAttribute( 'color', new THREE.Float32BufferAttribute( colors, 3 ) );
				geometry.setAttribute( 'size', new THREE.Float32BufferAttribute( sizes, 1 ).setUsage( THREE.DynamicDrawUsage ) );

				particleSystem = new THREE.Points( geometry, shaderMaterial );

				scene.add( particleSystem );

				renderer = new THREE.WebGLRenderer();
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );

				const container = document.getElementById( 'container' );
				container.appendChild( renderer.domElement );

				stats = new Stats();
				container.appendChild( stats.dom );

				//

				window.addEventListener( 'resize', onWindowResize );

			}

			function onWindowResize() {

				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();

				renderer.setSize( window.innerWidth, window.innerHeight );

			}

			function animate() {

				requestAnimationFrame( animate );

				render();
				stats.update();

			}

			function render() {

				const time = Date.now() * 0.005;

				particleSystem.rotation.z = 0.01 * time;

				const sizes = geometry.attributes.size.array;

				for ( let i = 0; i < particles; i ++ ) {

					sizes[ i ] = 10 * ( 1 + Math.sin( 0.1 * i + time ) );

				}

				geometry.attributes.size.needsUpdate = true;

				renderer.render( scene, camera );

			}

		</script>

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